SAM 27000 was the second of two Boeing VC-137C United States Air Force aircraft that were specifically configured and maintained for the use of the president of the United States. It used the call sign Air Force One when the president was on board, and at other times it used the call sign SAM 27000, with SAM indicating 'Special Air Mission.' The VC-137C serial number 72-7000 was a customized version of the Boeing 707 which entered service during the Nixon administration in 1972. It served all US presidents until George W. Bush and was retired in 2001. It is now on display at the Ronald Reagan Presidential Library.

Air Force One is the official air traffic control designated call sign for a United States Air Force aircraft carrying the president of the United States. In common parlance, the term is used to denote U.S. Air Force aircraft modified and used to transport the president and a metonym for the primary presidential aircraft, VC-25, although it can be used to refer to any Air Force aircraft the president travels on.